Polar Cases of Elasticity and Constant Elasticity

Self-Check Questions

Why is the demand curve with constant unitary elasticity concave?

Hint:

The demand curve with constant unitary elasticity is concave because the absolute value of declines in price are not identical. The left side of the curve starts with high prices, and then price falls by smaller amounts as it goes down toward the right side. This results in a slope of demand that is steeper on the left but flatter on the right, creating a curved, concave shape.

Why is the supply curve with constant unitary elasticity a straight line?

Hint:

The constant unitary elasticity is a straight line because the curve slopes upward and both price and quantity are increasing proportionally.